DEMO radioactive wastes: Decarburization, recycling and reuse by additive manufacturing

Abstract

Recycling is a real indicator of whether any nuclear industry is taking seriously about reducing its radioactive waste volume. Hence, manufacturing components starting from recycled activated material originated by DEMO reactor, with the relative manufacturing techniques, might be an important factor to support the environmental sustainability of fusion radioactive waste management. Accordingly, in this work the feasibility of recycling materials from decommissioned nuclear plants are presented.In the initial part, the powder production from activated steels AISI 316 L(N) and EUROFER and their use by Additive Manufacturing (AM) technologies is investigated as studied during EUROfusion Consortium funded activities. Chemical-physical parameters of this processed materials have been defined, together with the viability, of producing metal powders with an industrial VIGA (Vacuum Induction Gas Atomizer) facility. Experimental activities have been performed, aiming at powder production by VIGA and its characterization. A preliminary analysis of processing of these powders via selective laser melting (SLM) has been carried out. Additional results are presented for the experiments carried out on the decarburization of AISI 316 L(N) and EUROFER and experiments on the pollution of solid lithium orthosilicate breeder (Li4SiO4) coming from the refractory material, by simulating the thermal process of Li4SiO4 production or recycling, assessing the impact of platinum, zirconia, graphite and mullite on the quality of Li4SiO4 and on the feasibility of removing radioactive impurities.